The United States is home to approximately 50 snake species, with 21 considered venomous. About 150,000 pets are bitten by venomous snakes every year, and dogs are at higher risk in the warmer months, when snakes are more active. A venomous snake bite is an example of envenomation, and these injuries require prompt veterinary care. Keep reading to learn what you should know about venomous snakes to protect your four-legged friend.
Venomous snakes in the United States
The 21 venomous snake species are classified in one of two snake families, which include the Elapidae and Crotalidae families. Coral snakes are the only elapids found in North America, while Crotalidaie family members include rattlesnakes, copperheads, and water moccasins (i.e., cottonmouths). The crotalids are pit vipers, characterized by a flattened, arrow-shaped head and elliptical-shaped pupils.
Rattlesnakes are the largest venomous snakes in the United States, with 33 rattlesnake subspecies found throughout the country, most commonly in the southwestern deserts. Rattlesnakes are characterized by a segmented rattle at their tail tip that they vibrate when threatened. Rattlesnakes are responsible for about 65% of venomous snake bites reported in pets, but they typically don’t bite unless provoked. Every species has a different venom composition, but they all have neurotoxic and hemotoxic effects, causing pain, hemorrhaging, necrosis, and paralysis. Signs include bleeding from the bite wound, significant pain and area swelling, increased salivation, vomiting, and diarrhea.
The three coral snake species found in the United States typically have red, black, and yellow rings spanning their bodies. The rhyme, “Red and yellow, can kill a fellow; red and black, friend of Jack,” can help distinguish coral snakes from their nonvenomous counterparts, such as king snakes and milk snakes. Coral snakes are most commonly found in the southern states from Arizona to Florida. They have small, fixed fangs, and must chew on their prey to inject their venom, which is considered the most toxic in the United States, although their weak bite often prevents envenomation. Coral snake venom is neurotoxic, and blocks an important neurotransmitter (i.e., acetylcholine), causing weakness, paralysis, and possibly respiratory failure. The venom’s effects are usually delayed up to 13 hours, but once they develop, signs progress rapidly and include excessive salivation, generalized weakness, and muscle tremors.
Copperheads, which are named for their coppery red heads, are responsible for about 25% of venomous snake bites in pets. Five copperhead subspecies are found throughout the United States, with the northern copperhead covering the greatest range that includes Florida, Georgia, Alabama, Massachusetts, and Illinois. Their venom is hemotoxic, causing tissue damage in the immediate bite area. Signs are similar to those in rattlesnake-bitten dogs.
Water moccasins (i.e., cottonmouths) have white inner oral tissue that they display when threatened. They are found in the southeastern United States, ranging from Virginia to Florida, west to central Texas, and north to southern Illinois and Indiana. They are responsible for about 10% of venomous snake bites reported in pets. Water moccasin venom is hemotoxic, and signs are similar to other pit viper bites.
Treating venomous snake bites in dogs
Venomous snake bites are extremely serious, and your dog will require immediate veterinary care. If you can safely get a picture of the snake, that will help the veterinarian, because knowing the species will help determine treatment. On the way to your veterinarian, keep your dog as quiet and calm as possible, try to keep the bite wound below their heart level, and carry them rather than allowing them to walk. These measures will help decrease the toxin’s spread through your dog’s body. Please don’t attempt to cut or suck the bite wound, don’t place a tourniquet around the affected area and don’t place a hot or cold pack on the bite wound.Possible snake bite treatments include:
- Antivenin — This treatment directly counteracts the specific venom’s effects, halting further damage, but antivenin can’t reverse a previous injury. Antivenin is most effective when administered no longer than six hours after a snake bite.
- Intravenous (IV) fluids — IV fluids are necessary in many cases to support cardiovascular function.
- Anti-inflammatory medications — Nonsteroidal anti-inflammatories (NSAIDs) or corticosteroids may decrease inflammation and swelling. Ibuprofin is toxic to dogs, please do not attempt to medicate your dog without speaking to a veterinarian.
- Pain medications — Snake bite wounds, especially from pit vipers, are extremely painful, and your veterinarian will prescribe pain medication to alleviate your pet’s discomfort.
- Antibiotics — A snake’s mouth has numerous bacteria, and antibiotics may be recommended to prevent infection.
- Blood transfusion — A blood transfusion may be needed to address the venom’s hemotoxic effects.
- Oxygen therapy — Dogs experiencing respiratory difficulty will be supplemented with oxygen.
Approximately 80% of dogs who receive prompt veterinary care survive a venomous snake bite. They are typically hospitalized for several days, and will usually require follow-up care to assess wound healing and organ function. Factors that contribute to your dog’s prognosis include their age, size, current health status, the bite location, and time until the bite is treated.
Preventing snake bites in dogs
The good news—most snakes will bite only when provoked, and while not all snake bites can be avoided, you can take steps to lower your dog’s risk, including:
- Educate yourself — Know what snakes are in your area, and how to identify them.
- Keep your dog on a leash — When walking or hiking in areas known to have a high snake population, keep your dog on a leash, and be especially vigilant during the warmer months when snakes are more active.
- Avoid snake havens — Avoid areas such as wood piles, rock formations, and deep grass, where snakes tend to hide.
- Snake proof your yard — Keep your grass trimmed and rodents under control, to avoid attracting snakes.
- Consider positive reinforcement snake-avoidance training — If your location has a high snake population, consider finding a trainer to teach your dog how to avoid snakes.
- Rattlesnake vaccine — A rattlesnake vaccine is available that can protect dogs against western diamondback rattlesnake venom, and may protect against other rattlesnake species. Dogs who are bitten have less pain and a faster recovery, according to anecdotal reports, but no scientific studies support these claims.
Venomous snakes share our environment, and crossing paths is always a possibility. Ideally, your dog will never experience a venomous snake bite, but it is best to be prepared.